#pragma ident "$Id$"

/**
 * @file Xvt.hpp
 * Position and velocity as Triples, clock bias and drift as doubles.
 */

#ifndef GPSTK_XVT_INCLUDE
#define GPSTK_XVT_INCLUDE

//============================================================================
//
//  This file is part of GPSTk, the GPS Toolkit.
//
//  The GPSTk is free software; you can redistribute it and/or modify
//  it under the terms of the GNU Lesser General Public License as published
//  by the Free Software Foundation; either version 2.1 of the License, or
//  any later version.
//
//  The GPSTk is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with GPSTk; if not, write to the Free Software Foundation,
//  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
//
//  Copyright 2004, The University of Texas at Austin
//
//============================================================================

//============================================================================
//
//This software developed by Applied Research Laboratories at the University of
//Texas at Austin, under contract to an agency or agencies within the U.S.
//Department of Defense. The U.S. Government retains all rights to use,
//duplicate, distribute, disclose, or release this software.
//
//Pursuant to DoD Directive 523024
//
// DISTRIBUTION STATEMENT A: This software has been approved for public
//                           release, distribution is unlimited.
//
//=============================================================================


#include <iostream>
#include "Triple.hpp"
#include "EllipsoidModel.hpp"
#include "ReferenceFrame.hpp"
#include "GNSSconstants.hpp"

namespace gpstk
{
/** @addtogroup geodeticgroup */
//@{

/// Earth-Centered, Earth-Fixed Cartesian position, velocity, clock bias and drift
class Xvt
{
public:

    /// Default constructor
    Xvt() : x(0.,0.,0.), v(0.,0.,0.),
        clkbias(0.), clkdrift(0.),
        relcorr(0.), frame(ReferenceFrame::Unknown)
    {};

    /// Destructor.
    virtual ~Xvt()
    {}

    /// access the position, ECEF Cartesian in meters
    Triple getPos() throw()
    {
        return x;
    }

    /// access the velocity in m/s
    Triple getVel() throw()
    {
        return v;
    }

    /// access the clock bias, in second
    double getClockBias() throw()
    {
        return clkbias;
    }

    /// access the clock drift, in second/second
    double getClockDrift() throw()
    {
        return clkdrift;
    }

    /// access the relativity correction, in seconds
    double getRelativityCorr() throw()
    {
        return relcorr;
    }

    /// Compute and return the relativity correction (-2R dot V/c^2) in seconds
    /// NB -2*dot(R,V)/(c*c) = -4.4428e-10(s/sqrt(m)) * ecc * sqrt(A(m)) * sinE
    double computeRelativityCorrection(void);

    /// Given the position of a ground location, compute the range
    /// to the spacecraft position.
    /// @param rxPos ground position at broadcast time in ECEF.
    /// @param ellipsoid geodetic parameters.
    /// @param correction offset in meters (include any factors other
    /// than the SV clock correction and the relativity correction).
    /// @return Range in meters
    double preciseRho(const Triple& rxPos,
                      const EllipsoidModel& ellipsoid,
                      double correction = 0) const throw();

    // member data

    Triple x;        ///< Sat position ECEF Cartesian (X,Y,Z) meters
    Triple v;        ///< satellite velocity in ECEF Cartesian, meters/second
    double clkbias;  ///< Sat clock correction in seconds
    double clkdrift; ///< satellite clock drift in seconds/second
    double relcorr;  ///< relativity correction (standard 2R.V/c^2 term), seconds
    ReferenceFrame frame;   ///< reference frame of this data

}; // end class Xvt

//@}

}  // end namespace gpstk

/**
 * Output operator for Xvt
 * @param os output stream to which \c xvt is sent
 * @param xvt Xvt that is sent to \c os
 */
std::ostream& operator<<(std::ostream& os, const gpstk::Xvt& xvt) throw();

#endif // GPSTK_XVT_INCLUDE
